African American Children, Glycemic Control, and Type 2 Diabetes

Overview

Using a randomized, placebo-controlled trial design in subjects with vitamin D deficiency, the investigators propose to determine if vitamin D treatment improves glycemic control in vitamin D deficient subjects with T2DM. The investigators hypothesize that oral vitamin D treatment will improve glycemic control and ß-cell function in vitamin D deficient AA subjects with T2DM. The investigators further hypothesize that maintaining serum 25(OH)D concentrations above 20 ng/ml with oral supplementation of vitamin D will have additional glycemic control effects.

Current literature suggests that 25-hydroxyvitamin D (25(OH)D) is inversely related to risk of type 2 diabetes mellitus (T2DM). African Americans (AA) have significantly less 25(OH)D concentrations, greater chances of poor glycemic control compared to European Americans (EA). The primary objective is to evaluate if the differences in glycemic control in children with type 2 diabetes are explained by differences in serum concentrations of 25(OH)D. A secondary aim is to demonstrate that subjects with vitamin D deficiency (serum 25(OH)D \<20ng/ml) and T2DM who receive an 8 week of vitamin D treatment (50,000 IU oral vitamin D2/once per week) have greater improvement than subjects who receive placebo in glycemic control, as measured by HbA1c and endogenous insulin secretion, as assessed by area under the concentration-time curve (AUC) for mixed meal-stimulated C peptide, at 3 months after study drug administration. Research design: Randomized, placebo-controlled, double blind study design in children with T2DM and vitamin D deficiency. Glycemic control will be determined by HbA1C levels, fasting glucose and area under the curve (AUC) for glucose after a mixed meal tolerance test (MMTT). Measures of beta cell function will be determined by AUC for c-peptide and glucose after MMTT. This study is warranted in AA adolescents with T2DM as any positive interventions could have life long impact and will lead to future larger clinical trials.